linux-kernel - Re: [PATCH 05/13] kdb: Separate out "mdr" handling

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Date: Tue, 18 Jun 2024 12:29:29 +0100
From: Daniel Thompson <daniel.thompson@...aro.org>
To: Douglas Anderson <dianders@...omium.org>
Cc: kgdb-bugreport@...ts.sourceforge.net,
	Christophe JAILLET <christophe.jaillet@...adoo.fr>,
	Jason Wessel <jason.wessel@...driver.com>,
	Thorsten Blum <thorsten.blum@...lux.com>,
	Yuran Pereira <yuran.pereira@...mail.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 05/13] kdb: Separate out "mdr" handling

On Mon, Jun 17, 2024 at 05:34:39PM -0700, Douglas Anderson wrote:
> Though the "mdr" has a similar purpose to the other "md" commands in
> that they all display memory, the actual code to implement it has
> almost nothing in common with the rest of the commands. Separate
> things out.
>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> ---
>
>  kernel/debug/kdb/kdb_main.c | 65 ++++++++++++++++++-------------------
>  1 file changed, 31 insertions(+), 34 deletions(-)
>
> diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
> index 74db5c0cc5ad..c013b014a7d3 100644
> --- a/kernel/debug/kdb/kdb_main.c
> +++ b/kernel/debug/kdb/kdb_main.c
> @@ -1480,23 +1480,42 @@ int kdb_main_loop(kdb_reason_t reason, kdb_reason_t reason2, int error,
>  /*
>   * kdb_mdr - This function implements the guts of the 'mdr', memory

This is out of date (this function no longer implements the guts... it
just implements the whole thing).

With that change (and just to remind myself for next time):
Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>


>   * read command.
> - *	mdr  <addr arg>,<byte count>
> - * Inputs:
> - *	addr	Start address
> - *	count	Number of bytes
> - * Returns:
> - *	Always 0.  Any errors are detected and printed by kdb_getarea.
> + *	mdr  <addr arg> <byte count>
>   */
> -static int kdb_mdr(unsigned long addr, unsigned int count)
> +static int kdb_mdr(int argc, const char **argv)
>  {
> +	static unsigned long addr;
> +	static unsigned long count;
>  	unsigned char c;
> -	while (count--) {
> +	unsigned long i;
> +	int diag;
> +
> +	/*
> +	 * Parse args. The only valid options are argc == 2 (both address and
> +	 * byte_count provided) and argc == 0 ("repeat" AKA continue previous
> +	 * display).
> +	 */
> +	if (argc == 2) {
> +		int nextarg = 1;
> +
> +		diag = kdbgetaddrarg(argc, argv, &nextarg, &addr);
> +		if (diag)
> +			return diag;
> +		diag = kdbgetularg(argv[nextarg], &count);
> +		if (diag)
> +			return diag;
> +	} else if (argc != 0) {
> +		return KDB_ARGCOUNT;
> +	}
> +
> +	for (i = 0; i < count; i++) {
>  		if (kdb_getarea(c, addr))
>  			return 0;
>  		kdb_printf("%02x", c);
>  		addr++;
>  	}
>  	kdb_printf("\n");
> +
>  	return 0;
>  }
>
> @@ -1582,7 +1601,6 @@ static int kdb_md(int argc, const char **argv)
>  	bool symbolic = false;
>  	bool valid = false;
>  	bool phys = false;
> -	bool raw = false;
>
>  	kdbgetintenv("MDCOUNT", &mdcount);
>  	kdbgetintenv("RADIX", &radix);
> @@ -1591,12 +1609,7 @@ static int kdb_md(int argc, const char **argv)
>  	/* Assume 'md <addr>' and start with environment values */
>  	repeat = mdcount * 16 / bytesperword;
>
> -	if (strcmp(argv[0], "mdr") == 0) {
> -		if (argc == 2 || (argc == 0 && last_addr != 0))
> -			valid = raw = true;
> -		else
> -			return KDB_ARGCOUNT;
> -	} else if (isdigit(argv[0][2])) {
> +	if (isdigit(argv[0][2])) {
>  		bytesperword = (int)(argv[0][2] - '0');
>  		if (bytesperword == 0) {
>  			bytesperword = last_bytesperword;
> @@ -1631,10 +1644,7 @@ static int kdb_md(int argc, const char **argv)
>  		radix = last_radix;
>  		bytesperword = last_bytesperword;
>  		repeat = last_repeat;
> -		if (raw)
> -			mdcount = repeat;
> -		else
> -			mdcount = ((repeat * bytesperword) + 15) / 16;
> +		mdcount = ((repeat * bytesperword) + 15) / 16;
>  	}
>
>  	if (argc) {
> @@ -1650,10 +1660,7 @@ static int kdb_md(int argc, const char **argv)
>  			diag = kdbgetularg(argv[nextarg], &val);
>  			if (!diag) {
>  				mdcount = (int) val;
> -				if (raw)
> -					repeat = mdcount;
> -				else
> -					repeat = mdcount * 16 / bytesperword;
> +				repeat = mdcount * 16 / bytesperword;
>  			}
>  		}
>  		if (argc >= nextarg+1) {
> @@ -1663,16 +1670,6 @@ static int kdb_md(int argc, const char **argv)
>  		}
>  	}
>
> -	if (strcmp(argv[0], "mdr") == 0) {
> -		int ret;
> -		last_addr = addr;
> -		ret = kdb_mdr(addr, mdcount);
> -		last_addr += mdcount;
> -		last_repeat = mdcount;
> -		last_bytesperword = bytesperword; // to make REPEAT happy
> -		return ret;
> -	}
> -
>  	switch (radix) {
>  	case 10:
>  		fmtchar = 'd';
> @@ -2680,7 +2677,7 @@ static kdbtab_t maintab[] = {
>  		.flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
>  	},
>  	{	.name = "mdr",
> -		.func = kdb_md,
> +		.func = kdb_mdr,
>  		.usage = "<vaddr> <bytes>",
>  		.help = "Display RAM as a stream of raw bytes",
>  		.flags = KDB_ENABLE_MEM_READ | KDB_REPEAT_NO_ARGS,
> --
> 2.45.2.627.g7a2c4fd464-goog
>